Given these observations, a further assessment of the
functional immune responses elicited was performed. Antipneumococcal
phagocytosis represents the established primary
mechanism for protection against pneumococcal disease mediated
by anti-capsular polysaccharide antibodies [2]. Therefore,
opsonophagocytic activity (OPA) assays were performed in a subset
of participants to measure functional antibodies after administration
of PCV13 + TIV compared with administration of PCV13
alone.